Effects on thermal stress on predator-prey interactions

Type:

Master Thesis subject (30 ECTS)

programme:

EMBC+

Despite the sensitivity of coastal species to climate change, little research has been done on the effects of temperature fluctuations on population dynamics and species interactions. When closely interacting species display divergent responses to change, the outcome of their interactions may be altered. Direct predator–prey interactions are often important in determining the stability of biodiversity and ecosystem functioning. This thesis focuses on the hypothesis that temperature extremes as a stress factor, together with short-term (daily/weekly) temperature fluctuations, may alter population dynamics and ecosystem functioning. Specifically, the response of marine nematodes to such thermal stress conditions will be examined at the population level, including prey and predator species.
The performance of individual species in monospecific cultures will be compared with that in microcosms with different species together, to assess how competitive interactions are affected by thermal regime. Adding a predacious nematode to the artificial assemblages will allow to assess how thermal regime affects top-down controls on assemblages of bacterivorous nematodes. Both the monospecific and ‘mixed species’ experiments will assess nematode fitness under thermal stress (extreme episodes and daily fluctuations of temperature) in incubators with programmable thermal regimes. Measurements of population abundance and biomass will provide an indirect link to ecosystem functioning, since nematodes are a food source for higher trophic levels and since they impact microbial community structure and activity and in this way also organic matter mineralisation.